The aim of this study was to use two-dimensional electrophoresis (2-DE) coupled with multivariate principal component analysis (PCA) to characterize the quantitative changes in the
protein composition of the CEM T-
lymphoblastic leukemia cell line
after treatment with
bohemine (BOH), a synthetic olomoucin-derived
cyclin-dependent kinase inhibitor (CDKI). Cell classification, reflecting
protein patterns, clearly distinguished two main groups: one group consists of 9, 12 and 24 h treated BOH cells while the second is represented by the 0 and 24 h control untreated cells and the 6 h BOH-exposed CEM lymphoblasts. Discriminant
protein spots differentially expressed in the BOH-treated CEM cells were selected for identification by matrix assisted
laser desorption/ionization-mass spectrometry (MALDI-MS) or electrospray ionization-tandem MS (ESI-MS/MS). Five of the selected
protein spots were unequivocally identified as
alpha-enolase,
triosephosphate isomerase, eukaryotic
initiation factor 5A, and alpha- and beta-subunits of
Rho GDP-dissociation inhibitor 1. These
proteins, all significantly downregulated in CEM T-lymphoblast
leukemia in the course of BOH treatment, are known to play an important role in cellular functions such as glycolysis, protein biosynthesis, and cytoskeleton rearrangement. These results indicate that the cellular effects of
olomoucine-derived CDKIs are not dependent on their ability to inhibit CDKs and could be mediated by several factors such as a decrease in
protein synthesis and/or glycolysis which in turn diminishes the ability of
cancer cells to function.